LLC-PK1 cells express Na+-lactate cotransport in apical membranes after confluency.
Am J Physiol
; 255(6 Pt 2): F1249-55, 1988 Dec.
Article
in En
| MEDLINE
| ID: mdl-3202188
ABSTRACT
L-[3H]lactate uptake was characterized in LLC-PK1 cell apical membrane vesicles obtained by intensive culture on microcarrier beads. The apical membrane preparation technique involved MgCl2 precipitation. Na+-dependent L-[3H]lactate uptake was present only after confluency; its appearance paralleled the subcellular localization of aminopeptidase in apical membranes. L-[3H]lactate uptake was Na+-dependent and electrogenic. Only the Na+-dependent component of L-[3H]lactate uptake was saturable with one family of independent carriers. The apparent affinity constant was 1.1 +/- 0.25 mM and the apparent maximal velocity was 29 +/- 3 nmol.mg-1.min-1. The Na+-lactate cotransport stoichiometry was 2 Na+ for 1 lactate. The specificity of the L-lactate transport system was compatible with that of the monocarboxylic acid pathway described previously in brush-border membranes of kidney cortex and discrete from the tricarboxylic acid carrier, the D-glucose transporter, and the general pathway for anions. The LLC-PK1 cell line appears to be a useful tool for study of the regulation of L-lactate uptake and biosynthesis of the renal monocarboxylic acid transporter.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Sodium
/
Carrier Proteins
/
Cell Membrane
/
Monocarboxylic Acid Transporters
/
Symporters
/
Lactates
Limits:
Animals
Language:
En
Journal:
Am J Physiol
Year:
1988
Document type:
Article
Affiliation country:
France